diff --git a/bok-macro/src/pkgs.rs b/bok-macro/src/pkgs.rs
index 13cbebd..d09911c 100644
--- a/bok-macro/src/pkgs.rs
+++ b/bok-macro/src/pkgs.rs
@@ -276,7 +276,7 @@ pub(crate) fn deps_build(
             *
         }
         #[::macro_magic::export_tokens(#pkg_trait)]
-        pub trait #pkg_trait {
+        pub trait #pkg_trait: ::bok::Repository {
             #(fn #deps(&self) -> ::std::boxed::Box<dyn ::bok::Pkg>;)
             *
         }
diff --git a/bok-macro/src/repos.rs b/bok-macro/src/repos.rs
index d20307a..25411a5 100644
--- a/bok-macro/src/repos.rs
+++ b/bok-macro/src/repos.rs
@@ -227,6 +227,9 @@ pub(crate) fn derive_repository(input: TokenStream) -> TokenStream {
                 _ => None,
                 }
             }
+            fn as_any(&self) -> &dyn ::std::any::Any {
+                self
+            }
         }
     }.into()
 }
diff --git a/bok-utils/src/repos/pkgs/one.rs b/bok-utils/src/repos/pkgs/one.rs
index defe0f0..e775677 100644
--- a/bok-utils/src/repos/pkgs/one.rs
+++ b/bok-utils/src/repos/pkgs/one.rs
@@ -48,7 +48,7 @@ impl ::bok::Pkg for One {
     }
     fn dependencies_set(
         &self,
-        _repo: ::std::sync::Arc<dyn ::bok::Repository>,
+        repo: ::std::sync::Arc<dyn ::bok::Repository>,
         _build: &::bok::deps::Build,
         _runtime: &::bok::deps::Runtime,
     ) -> Result<(), ()> {
diff --git a/bok-utils/src/repos/pkgs/two.rs b/bok-utils/src/repos/pkgs/two.rs
index 188c223..e59746a 100644
--- a/bok-utils/src/repos/pkgs/two.rs
+++ b/bok-utils/src/repos/pkgs/two.rs
@@ -45,10 +45,16 @@ impl ::std::default::Default for Two {
 impl ::bok::Pkg for Two {
     fn dependencies_set(
         &self,
-        _repo: ::std::sync::Arc<dyn ::bok::Repository>,
+        repo: ::std::sync::Arc<dyn ::bok::Repository>,
         _build: &::bok::deps::Build,
         _runtime: &::bok::deps::Runtime,
     ) -> Result<(), ()> {
+        let repo_any = repo.as_any();
+        let Some(actual_repo) = repo_any.downcast_ref::<R>() else {
+            return Err(());
+        };
+        let _ = actual_repo.one();
+
         Ok(())
     }
 }
diff --git a/bok/src/lib.rs b/bok/src/lib.rs
index 6a686db..ba8575c 100644
--- a/bok/src/lib.rs
+++ b/bok/src/lib.rs
@@ -52,6 +52,7 @@ pub trait Repository: ::core::fmt::Debug {
     fn path(&self) -> Path<RepoName>;
     fn pkg_list(&self) -> &[&'static str];
     fn get(&self, pkg_name: &str) -> Option<::std::boxed::Box<dyn Pkg>>;
+    fn as_any(&self) -> &dyn ::std::any::Any;
 }
 
 /// This is an empty Package List.
@@ -75,6 +76,9 @@ impl Repository for RepositoryEmpty {
     fn get(&self, _pkg_name: &str) -> Option<::std::boxed::Box<dyn Pkg>> {
         None
     }
+    fn as_any(&self) -> &dyn ::std::any::Any {
+        self
+    }
 }
 
 /// Print the code of the package